Vader was supposed to be a killing machine and was in the early days of the empire killing the last few Jedi. Lucas just filmed that scene slow like that to resemble a kendo match that a samurai master and fallen apprentice would fight and buildup to obi-wan's sacrificing himself to then become one with the force.

Not sure. I guess it depends on your reading level and whether you start with the prequel or read them in order of publication. Also if you're gonna read Foundation you're have to read the Robots and the Empire series' as well so if you haven't read either I would estimate anywhere from 8 months to a year.